<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>发送消息给服务器</title>

    <script type="text/javascript">

        function sendMessage() {
            let text = document.getElementById('7').value;
            document.getElementById('8').value = text;
        }

    </script>
</head>
<body>

    message:<br>
    <input type="text" name="sendInput" id = "7">
    <br><br>
    <input type="submit" name="send" title="send" onclick="sendMessage()">

    <br><br>
    back:<br>
    <input type="text" name="reveiceInput" id = "8">

</body>
</html>